Ion beam remote control device haivng pulse shaping and restoring means



June 25, 1968 G. BREYNAT ETAL 3,390,342

ION BEAM REMOTE CONTROL DEVICE HAVING PULSE SHAPING AND RESTORING MEANSFiled July 20. 1965 3 Sheets-Sheet 1 PULSE summon DIFFEREITIATORINTEGRATOR ix ri [x Av r H 3 l I 2 fi 'ia ronuaa qcfima FIG! l: he

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ION BEAM REMOTE CONTROL DEVICE HAVING PULSE SHAPING AND RESTORING MEANS5 Sheets-Sheet 2 Filed July 20. 1965 FIG.3

June 1958 G. BREYNAT ETAL 3,390,342

ION BEAM REMOTE CONTROL DEVICE HAVING PULSE SHAPING AND RESTORING MEANSFiled July 20, 1965 3 Sheets-Sheet 5 United States Patent 4 Claims. 61.328-227) The present invention relates to a device for theremote-control of the ion-beam created by an ion-source submitted to ahigh frequency electric field, said device having its pulse-generatorlocated near a control desk far from the ion-source.

More precisely, the present invention relates to an ionbeam remotecontrol device which is characterized in that it comprises apulse-generator which emits rectangular signals and is adapted tocontrol a differentiator and impedance reducer, the resulting thusdifferentiated signal being transmitted via a long coaxial cable to astepdown pulse-transformer adapted to actuate an integrator which inturn, feeds a reconstituted rectangular but phaseinverted signal to akeyer adapted to provide the alternate blocking and unblocking of a highfrequency oscillator.

According to a further feature of the invention, said transformercomprises, inside a first insulating tube around which is wound thetransformer primary winding, a second insulating tube coaxial therewithand forming a well at the bottom of which is located the transformersecondary winding.

The duration of the ion pulses is adjusted by the pulse generator, atthe control desk. Once it has been differentiated, the signal can betransmitted, at low impedance, to the primary of the transformer, via along coaxial cable. The voltage at the exit of the transformer is chosenhigh enough for actuating the integrator without the need of anamplifying stage; once it has been restored by the integrator, thesignal controls a conventional keyer-oscillator unit which, in turn,actuates the ion-source.

The features of the present invention will be disclosed hereafter,reference being had to the accompanying drawing in which:

FIG. 1 is a block-diagram of the device according to the invention;

FIG. 2 shows the differentiator and impedance reducer of said device(reference 2 in FIG. 1);

FIG. 3 shows the step-down pulse-transformer of said device (reference 4in FIG. 1);

FIG. 4 shows the lower portion of the transformer of FIG. 3, on :anenlarged scale;

FIG. 5 shows the integrator of said device (reference 5 in FIG. 1); and

FIG. 6 shows the keyer-oscillator of said device (reference 6 in FIG.1).

From the control desk to the ion source, the device according to theinvention successively comprises (as shown by FIG. 1) a pulse-generator1 the output of which is connected to the input of a unit 2 acting as adifferentiator and an impedance reducer, a long coaxial cable 3, astep-down pulse-transformer 4, an integrator 5 and a keyer-oscillatorunit 6, and later being coupled to ion-source 7.

Pulse-generator 1, of a conventional type, and differentiator 2 arelocated in the vicinity of the control-desk, whereas transformer 4 andthe other units are mounted in the vicinity of the ion-source,differentiator 2 and transformer 4 being connected by long coaxial cable3.

As more clearly shown in FIG. 2, unit 2 comprises a resistor-capacitorcircuit for deriving signals and two push= pull mounted transistors 16and 17.

The step-down pulse-transformer 4 is insulated up to about, e.g., 200kv. Between its primary (connected to unit 2 by long coaxial cable 3)and its secondary (connected to integrator 5), this transformerwithstands all the acceleration voltage, and it restores the pulsesapplied thereto, without any substantial distortion.

As shown in FIG. 3, the primary 20 of transformer 4 is wound around aspool of nylon or of a similar material, and it comprises 300 turns. Theimpedance of said primary must be high enough with respect to the cableresistance ohms in the specific example disclosed) in order to avoidover-shoots whatever he the characteristics of the pulses provided bygenerator 1.

The secondary 22 of transformer 4, formed of 40 turns, is also woundaround a spool 23 of nylon" in the central portion of which is a core offerrite 24. Insulation is ensured by a tube 25 of Haeffelite mountedinside spool 21 of the primary and the height of which is about 60 in.cm.), whereas that of spools 21 and 23 is of about 5 to 6 in. (12 to 15cm.). A large diameter torus 27 defines an equipotential surface whichis wide enough for preventing ionization in connection cables.

Within tube 25 and coaxial therewith is mounted a well 26 of Araldite,at the bottom of which is located spool 23 around which is wound thesecondary. Well 26 and tube 25 are filled with transformer-oil which hasbeen dehydrated before filling.

The fiip-fiop integrator stage 5 shown in FIG. 5 comprises its ownsource of direct voltage from the alternating voltage furnished by thetransformer of unit 6; stage 5 can also be fed independently; azener-diode 30 provides the stabilized voltage required for feeding theflip-flop. The latter is constituted by a resistor 31 and a tunnel diode32. The output signal 33 of the pulse-transformer attacks said flip-flopthrough transistor 34 which acts as an impedance reducer. The resultingsignal is amplified by transistor 35 and fed at low impedance to theinput of unit 6, through transistor 36.

The keyer-oscillator unit 6 (FIG. 6) essentially comprises an amplifiertube 40 and an oscillator 41, the grid of which is normally kept at anegative voltage by tube 40, said oscillator 41 being coupled toion-source 7 by means of two rings 12 and 13.

Ion-source 7, of a conventional type, consists in an envelope 8 providedwith an extraction slit 11 and an anode 10 for applying the extractionfield; two rings 12 and 13 connected to HF oscillator 6 serve to createa high frequency electric field in ion-source 7.

The above-described device operates as follows: pulsegenerator 1 emitspositive rectangular signals 15, the dura tion and repetition frequencyof which can be adjusted at will. These signals are differentiated andhave their impedance reduced by stage 2 which, in turn, emits signals 18which are fed, via the long coaxial cable 3 (which is for instance 500feet long), to the primary of step-down pulse-transformer 4. The thusdifferentiated signals cannot be distorted by said pulse-transformer.The latter, at the output of its secondary, provides pulses the level ofwhich is about $4 of the voltage of the pulses at the input of theprimary; said transformer 4 is an impedance matching device forterminating the coaxial cable 3; flipfiop integrator stage 5, fed by thesignal 33 emitted by the secondary, in turn, feeds a reconstitutedrectangular but phase-inverted (therefore negative) signal 42 to theinput of stage 6, i.e., to the control-grid of amplifier-tube 40, andthe latter ensures the alternate blocking and unblocking of oscillator41, which thus generates electric oscillations. Whenever, a signal 42unblocks osci lator 51, the ionization due to the high frequencyelectric field in the ion-source 7 is very high, and the ionic fiowthrough extraction-slit 11 of the ion-source is maximum, whereas,whenever oscillator 41 is blocked, the ionic fiow vanishes.

The device forming the object of the present invention can in particularbe applied to the production of a pulsed ion-beam intended to generate abeam of neutrons.

What is claimed is:

1. A device for remote control of an ion beam from an ion sourcesubjected to a high frequency electric field comprising, connected inseries, a pulse generator emitting rectangular signals, adifferentiating and impedance reducing unit connected to said generatorand actuated by said generator and altering the signals emitted by saidgenerator, said generator and said unit being located adjacent a controldesk, a long coaxial cable, one end of said cable being connected tosaid unit, a step-down pulse transformer having primary and secondarywindings connected to the other end of said cable, said primary windings of said transformer receiving the differentiated signals emitted bysaid unit, an integrator connected to said secondary windings andactuated by the signals emitted by said secondary windings, saidintegrator emitting reconstituted, rectangular, phase-inverted signals,a keyer connected to said integrator and actuated by the reconstitutedsignals, a high frequency oscillator connected to said keyer andalternately blocked and unblocked by said keyer, and two rings mountedon said ion source and connected to said oscillator generating a highfrequency electric field in said ion source whereby when said oscillatoris blocked the ionic flow is substantially zero and when said oscillatoris unblocked the ionic flow is maximum.

Cir

2, A device as described in claim 1, said differentiating and impedancereducing unit comprising a resistor capacity circuit and two push-pullmounted transistors.

3. A device as described in claim 1, said step-down pulse transformercomprising a first insulating tube, said primary winding being mountedaround said first tube, a second insulating tube mounted inside saidfirst tube, a well of insulating material within said second insulatingtube, a spool at the bottom of said well, a core of ferrite within saidspool, said secondary winding being mounted around said spool and alarge diameter toru on said first tube defining an equipotential surfacepreventing ionization in connection cables.

4. A device as described in claim 1, said keyer oscillator comprising anamplifier tube, a control grid for said tube receiving the signalsemitted by said integrator, an oscillator and a. grid for saidoscillator normally kept at negative voltage by said tube.

References Cited UNITED STATES PATENTS 1,046,714 12/1912 Anthony 178-682,620,446 12/1952 Levine 250-83.6 2,621,251 12/1952 Aigrain 325-422,676,204 4/1954 Snijders 178-66 3,062,913 11/1962 Myrick 17866 JAMES W.LAWRENCE, Primary Examiner.

STANLEY D. SCHLOSSER, Examiner,

P. C. DEMEO, Assistant Examinerv

1. A DEVICE FOR REMOTE CONTROL OF AN ION BEAM FROM AN ION SOURCESUBJECTED TO A HIGH FREQUENCY ELECTRIC FIELD COMPRISING, CONNECTED INSERIES, A PULSE GENERATOR EMITTING RECTANGULAR SIGNALS, ADIFFERENTIATING AND IMPEDANCE REDUCING UNIT CONNECTED TO SAID GENERATORAND ACTUATED BY SAID GENERATOR AND ALTERING THE SIGNALS EMITTED BY SAIDGENERATOR, SAID GENERATOR AND SAID UNIT BEING LOCATED ADJACENT A CONTROLDESK, A LONG COAXIAL CABLE, ONE END OF SAID CABLE BEING CONNECTED TOSAID UNIT, A STEP-DOWN PULSE TRANSFORMER HAVING PRIMARY AND SECONDARYWINDINGS CONNECTED TO THE OTHER END OF SAID CABLE, SAID PRIMARY WINDINGSOF SAID TRANSFORMER RECEIVING THE DIFFERENTIATED SIGNALS EMITTED BY SAIDUNIT, AN INTEGRATOR CONNECTED TO SAID SECONDARY WINDINGS AND ACTUATED BYTHE SIGNALS EMITTED BY SAID SECONDARY WINDINGS, SAID INTEGRATOR EMITTINGRECONSTITUTED, RECTANGULAR, PHASE-INVERTED SIGNALS, A KEYER CONNECTED TOSAID INTEGRATOR AND ACTUATED BY THE RECONSTITUTED SIGNALS, A HIGHFREQUENCY OSCILLATOR CONNECTED TO SAID KEYER AND ALTERNATELY BLOCKED ANDUNBLOCKED BY SAID KEYER, AND TWO RINGS MOUNTED ON SAID ION SOURCE ANDCONNECTED TO SAID OSCILLATOR GENERATING A HIGH FREQUENCY ELECTRIC FIELDIN SAID ION SOURCE WHEREBY WHEN SAID OSCILLATOR IS BLOCKED THE IONICFLOW IS SUBSTANTIALLY ZERO AND WHEN SAID OSCILLATOR IS UNBLOCKED THEIONIC FLOW IS MAXIMUM.